Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly, idempotent, openWorld and non-destructive, so the safety profile is covered. The description adds some behavioral nuance (verified data only 'when the church itself supplied it', plus provenance and sameAs links), but does not discuss error behavior for a missing slug or rate/auth constraints.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with purpose, then example identifiers, then return contents; no filler sentences. Slightly long on enumerating return fields, but tight overall.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With an output schema present, the return-field enumeration is partly redundant, and the safety profile is covered by annotations, so the description is sufficient for calling correctly. It would be stronger with explicit routing against find_churches_near and failure behavior for unknown slugs.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, and both params are documented with examples in the schema, so the baseline is 3. The description reiterates country/slug plus the composite id format, which is mildly additive but largely duplicates structured data.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb+resource ('One church ... by country and slug') and gives a concrete composite-id example (lb:church:united-states/saint-josephs), so an agent knows it fetches a single church record. It does not explicitly contrast itself with the closest siblings (find_churches_near, heritage_lookup, denomination_compare), though 'One church' implies a singular lookup.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Usage is implied: call this when you already have a country and slug for one specific church. There is no explicit when-to-use/when-not or named alternative (e.g. use find_churches_near to discover churches first), leaving the agent to infer routing. The example values help but are not routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.